Acidified npkscl fertilizer granules for fertigation

Abstract

Acidic fertilizer granules, methods for producing the same, and methods for their use in fertigation, are disclosed. The acidic fertilizer granule can contain 1 wt. % to 45 wt. % of nitrogen; 1 wt. % to 45 wt. % of phosphorus; 1 wt. % to 45 wt. % of potassium; 0.1 wt. % to 20 wt. % of sulfur; and 1 wt. % to 45 wt. % of chlorine, wherein the granule contains an effective amount of an inorganic acid sufficient to form a solution having a pH of less than 4 when 10 grams of the fertilizer granule(s) is dissolved in 100 ml of water having a pH of 7 before the fertilizer granule(s) is dissolved in the water.

1 . An acidic fertilizer granule comprising:
 1 wt. % to 45 wt. % of nitrogen;   1 wt. % to 45 wt. % of phosphorus;   1 wt. % to 45 wt. % of potassium;   0.1 wt. % to 20 wt. % of sulfur; and   1 wt. % to 45 wt. % of chlorine,   
       wherein the granule comprises an effective amount of an inorganic acid sufficient to form a solution having a pH of less than 4 when 10 grams of the fertilizer granule(s) is dissolved in 100 ml of water having a pH of 7 before the fertilizer granule(s) is dissolved in the water. 
     
     
         2 . The fertilizer granule of  claim 1 , wherein the inorganic acid is distributed throughout the granule. 
     
     
         3 . The fertilizer granule of  claim 1 , wherein the amount of the inorganic acid in the granule is sufficient to form a solution having a pH of less than 3 when 10 grams of the fertilizer granule(s) is dissolved in 100 ml of water having a pH of 7 before the fertilizer granule is dissolved in the water. 
     
     
         4 . The fertilizer granule of  claim 1 , comprising 2 wt. % or more of the inorganic acid. 
     
     
         5 . The fertilizer granule of  claim 1 , comprising 8 wt. % or more of the inorganic acid. 
     
     
         6 . The fertilizer granule of  claim 1 , wherein the inorganic acid comprises sulfuric acid, hydrochloric acid, nitric acid, or any combinations thereof. 
     
     
         7 . The fertilizer granule of  claim 6 , wherein the inorganic acid comprises sulfuric acid. 
     
     
         8 . The fertilizer granule of  claim 1 , further comprising a secondary nutrient and/or a micronutrient. 
     
     
         9 . The fertilizer granule of  claim 1 , comprising 2 to 40 wt. % of nitrogen, and at least a portion of nitrogen is present as ammonium. 
     
     
         10 . The fertilizer granule of  claim 1 , comprising 2 to 40 wt. % of phosphorus, and at least a portion of phosphorus is present as phosphate. 
     
     
         11 . The fertilizer granule of  claim 1 , comprising 2 to 40 wt. % of potassium, and at least a portion of potassium is present as potassium salt. 
     
     
         12 . The fertilizer granule of  claim 1 , comprising 2 to 40 wt. % of chlorine, and at least a portion of chlorine is present as chloride. 
     
     
         13 . The fertilizer granule of  claim 1 , comprising 0.5 to 15 wt. % of sulfur and at least a portion of sulfur is present as sulfate. 
     
     
         14 . The fertilizer granule of  claim 1 , comprising 17 to 21 wt. % of nitrogen, 17 to 21 wt. % of phosphorus, 17 to 21 wt. % of potassium, 2 to 5 wt. % of sulfur, and 13 to 19 wt. % of chlorine. 
     
     
         15 . The fertilizer granule of  claim 1 , comprising 8 to 12 wt. % of sulfuric acid. 
     
     
         16 . The fertilizer granule of  claim 1 , having moisture content of less than 2 wt. %, or less than 1 wt. %, measured at 50° C. 
     
     
         17 . The fertilizer granule of  claim 1 , comprised in a fertilizer blend comprising the fertilizer granule and an additional fertilizer. 
     
     
         18 . A method of making the acidic fertilizer granule of  claim 1 , comprising:
 adding an inorganic acid to a mixture to form an acidified mixture, wherein the acidified mixture comprises nitrogen, phosphorus, potassium, sulfur, and chlorine; and   granulating the acidified mixture.   
     
     
         19 . A method of fertigation, the method comprising:
 combining the acidic fertilizer granule of  claim 1  with water to form a fertigation solution having a pH less than 4;   optionally combining the fertigation solution with additional water to form a fertilizer solution; and   applying the fertigation solution and/or the fertilizer solution to a soil and/or a crop.   
     
     
         20 . The method of  claim 19 , wherein combining the acidic fertilizer granule with the water decreases the pH of the water from a pH of greater than 4 to a pH of less than 4.